Reactive-Distillation Process for Direct Hydration of Cyclohexene to Produce Cyclohexanol

Abstract

Cyclohexanol is an important precursor in synthesizing intermediates of Nylons and also plasticizers. In this paper, a plantwide reactive-distillation process for the production of cyclohexanol by direct hydration of cyclohexene with water has been studied. Design with excess water is needed to economically increase conversion of cyclohexene to 99.9%. The optimal design of the proposed flowsheet also makes use of the natural liquid–liquid splitting of the binary cyclohexanol–water azeotrope. Realistic fresh cyclohexene feed with impurity of cyclohexane was also considered. This inert is designed to leave the system in the organic outlet stream of a decanter on top of the reactive-distillation column. The reboiler duty requirement of the proposed design flowsheet is compared with existing processes in open literature. It is found that significant energy savings can be realized by using this design.

Greenhouse gas emissions reduction by process intensification: Reactive distillation column with side decanter

“…Case a of Ye et al (2014) 39 and Chen et al ( 2014) 40 reach similar values of energy consumption for a reactive distillation with stoichiometric feed: very high energy consumption. The infeasibility of the RD process is found to be mainly due to the low catalyst effectiveness (case b), rather than the slow reaction rate or limitation of catalyst loading in the RD column.…”

“…In the reactive distillation column proposed with an excess of water 40 instead of the reactor of the Asahi process, the excess of water allows a total conversion of cyclohexene in the reactive distillation column. A decanter takes advantage of the phase split between water and cyclohexanol to recycle the excess of water.…”

“…Despite using reactive distillation, an excess of water is helpful to take advantages of the phase split at the output streams. 40 The studies that provide an energy consumption estimation are further discussed and compared in the results section.…”

Phase and chemical equilibria in multicomponent fluid systems with a chemical reaction

“…For instance, data on multicomponent systems, in which not all of the substances react, are presented in some publications (not cited in this review). As a rule, such investigations deal with the ways of arrangement of reactive distillation processes and do not give 72 represents a recent research of this type considering direct hydration of cyclohexene for the production of cyclohexanol. Since the number of studies of this type of ternary systems is scanty, as it was noticed in the introduction to this review, data on the combined phase and chemical equilibrium in the cyclohexene ± water ± cyclohexanol system might have been of interest.…”

Effect of boiling point rankings and feed locations on the applicability of reactive distillation to quaternary systems

“…Furthermore, the implementation of RD is very appealing to other reactions involving reversible quaternary systems (A + B ⇌ C + D) and ternary systems (A + B ⇌ C and A ⇌ B + C). Some examples include the hydration of cyclohexene to obtain cyclohexanol (Chen et al, 2014), dehydration of glycerol to acetol (Chiu et al, 2006), isoamyl acetate production via esterification of isoamyl alcohol and acetic acid (González et al, 2017) and diethyl carbonate synthesis via trans-esterification of propylene carbonate and ethanol (Wang et al, 2014).…”